Abstract
Human amniotic epithelial cells (hAECs) are non-immunogenic epithelial cells that can develop into cells of all three germline lineages. However, a refined clinically reliable method is required to optimize the preparation and banking procedures of hAECs for their successful translation into clinical studies. With the goal of establishing standardized clinically applicable hAECs cultured cells, we described the use of a powerful epithelial cell culture technique, termed Conditionally Reprogrammed Cells (CRC) for ex vivo expansion of hAECs. The well-established CRC culture method uses a Rho kinase inhibitor (Y-27632) and J2 mouse fibroblast feeder cells to drive the indefinite proliferation of all known epithelial cell types. In this study, we used an optimized CRC protocol to successfully culture hAECs in a CRC medium supplemented with xenogen-free human serum. We established that hAECs thrive under the CRC conditions for over 5 passages while still expressing pluripotent stem markers (OCT-4, SOX-2 and NANOG) and non-immunogenic markers (CD80, CD86 and HLA-G) suggesting that even late-passage hAECs retain their privileged phenotype. The hAECs-CRC cells were infected with a puromycin-selectable lentivirus expressing luciferase and GFP (green fluorescent protein) and stably selected with puromycin. The hAECs expressing GFP were injected subcutaneously into the flanks of Athymic and C57BL6 mice to check the tolerability and stability of cells against the immune system. Chemiluminescence imaging confirmed the presence and viability of cells at days 2, 5, and 42 without acute inflammation or any tumor formation. Collectively, these data indicate that the CRC approach offers a novel solution to expanding hAECs in humanized conditions for future clinical uses, while retaining their primary phenotype.